This invention relates in general to a method and apparatus to provide a manual selective position control system, and more particularly to a method and apparatus to selectively control a vertical down or up secured position of an agricultural or other mobile tool using a hydraulic system.
This invention generally relates to the invention disclosed with U.S. Pat. No. 4,825,655 which is incorporated herein in its entirety, that relates to fluid cylinder systems and allows for control of piston stroke position.
Historically, the position of tool penetration for agricultural equipment, or other soil penetration or soil discharge equipment, has been set by mechanical devices which restrict the extension or retraction of hydraulic cylinders. The cylinder(s) is typically mounted between the frame of the implement and the leg of the implement carrier wheel. Thus, height of the frame above the ground, which determines tool penetration, could be hydraulically changed to a more shallow position (i.e., less tool penetration) but not to a yet lower position because of mechanical restrictions.
The prior approach is still in use but does not offer ready access to implement position settings encountered, for example, in farm tillage operations, such as two typical working positions; namely, a tillage depth and an end of the field turning depth. These two positions are typically followed by a full raise, or transport position, of the implement.
Another prior approach still in use is to set the mechanical depth controls to establish a maximum depth for the farm implement. Working positions and turning positions are then searched for by the operator working the hydraulic lever to arrive at certain positions, such as a working depth or turning depth. The maximum depth would be used for deep weeds, leveling of rough ground, or loosen compacted ground.
It is difficult for an operator to find a desired position without cylinder stops because hydraulic flows are in the 10 to 20 gallons per minute range and ground speed typically at six to eight miles per hour. The operator has to gauge implement position by eye rather than from a predetermined set point.
Another example would be soil cutting position and dumping position for the clam shell of a soil mover. Variations in position, for both cut and dump, are typically in the range of one to two inches and are difficult to establish by eye or resistance.
Recently automatic depth control systems have been brought onto the market which control the extension and retraction of the implement carrier cylinder in order to hold a select depth. Such automatic depth control systems are disclosed in Patent Numbers: U.S. Pat. No. 6,216,794 B1; U.S. Pat. No. 6,216,795 B1; U.S. Pat. No. 6,164,385; and U.S. Pat. No. 6,085,846.
Another non-automatic system is sold by John Deere. It is referred to as TouchSet Hydraulics. It is a proprietary system incorporating both a John Deere tractor and a John Deere implement; therefore, restrictive in its application. It further requires a nine pin electrical wiring harness to connect each implement cylinder individually. It further does not have programmable slaving functions. It further does not incorporate a remote solenoid valve or the rebound valve of U.S. Pat. No. 4,825,655.
Thus there is a need for an efficient system that is adaptable to on-the-go farming or industrial practices and offers better control of the working positions for operations on varying soil textures (sand, silt and clay), weather effects upon these soils, and control for various implements, applications and field conditions. In particular, a need for a system which has universal application to tractors and implements.